BRPI0922889B1 - DRIVING ARRANGEMENT FOR PUMP AND PUMP ASSEMBLY - Google Patents

Abstract

drive arrangement for pump and pump assembly the present invention relates to the drive arrangement (11) for a pump, compressor or similar, adapted to provide alternating pressure in at least two chambers (27a, 27b, 27 ', 27 " ), such as chambers of a pump or compressor, as a result of alternating movement of a bar element (23) .The bar element is connected to two movable faces of the pressure chamber which are pistons (21a, 21b) or pistons presenting fluid connection to said chambers, whose bar element (22) is alternately supported in a housing (19). the drive arrangement additionally comprises an electric motor (31) which is adapted to provide the alternating movement of the bar element ( 23) The bar element extends through the rotor (31b) of the electric motor (31) The electric motor is a rotary electric motor The invention also relates to a pump assembly with a plurality of these drive arrangements.

Description

Descriptive Report of the Invention Patent for PUMP ACTIVATION FOR PUMP AND PUMP ASSEMBLY.

[001] The present invention relates, in general, to a drive arrangement for pumps and compressors. The invention also relates to the assembly of such a drive arrangement with a plurality of pumps, for which the drive arrangement is particularly well suited.

BACKGROUND

[002] Various types of drive arrangements for pumps and compressors are known. The type is typically chosen based on parameters such as weight, volume, strength, speed, sound level, vibration level, reliability, available power supply, and price, etc. For example, for subsea applications, a reliable drive arrangement that requires less maintenance and can be driven with hydraulics or electric power is particularly desired.

[003] From US Patent Publication 7,287,595, it is known to use an electric motor to drive a hydraulic piston to supply hydraulic pressure in an underwater environment. The electric motor is connected to a ball screw assembly 170 via planetary gear 190. A piston rod 134, which, at its opposite end, is attached to a hydraulic piston 130, is connected to the ball screw. The assembly can thus provide hydraulic pressure by means of electrical energy to the electric motor, whose hydraulic pressure is accumulated in an accumulator 142. In this way, it is prevented that hydraulic umbilicals have to be guided from the sea surface to a well submarine, for example.

[004] In the solution shown in US 7,287,595, it is worth noting that the stroke length of piston rod 134 is limited to the area between the

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2/27 planetary gear 190 and outer limit (lower) for movement in ball screw assembly 170.

[005] US Patent Publication 4,145,165 describes a long stroke pump that features a threaded rod that extends through the rotor of an electric motor. When the rotor operates, the rod will be moved axially in an alternating path due to the threaded engagement with the rotor. The two ends of the rod act as two pistons that provide pumping action with the repeated entry and exit of the two adjacent chambers.

[006] In addition, the US Patent Application Publication

2009/0053074, which was published on February 26, 2009, describes a similar displacement pump that uses an electric linear motor to provide a similar reciprocating motion of a piston rod. This pump uses pistons at the respective ends of a piston rod.

[007] Furthermore, it is known to provide piston movement with the connection of the piston rod, directly or indirectly, to a crankshaft (see figure 1) or to a flywheel. Such crankshaft or flywheel will have an axial direction transverse to the piston stroke length. This makes the assembly demanding space. In addition, the stroke length is limited by the dimensions of the crankshaft or flywheel in the radial direction.

[008] It is an objective of the present invention to provide a drive arrangement for pumps and compressors that does not have the above mentioned disadvantages, and that additionally exhibits additional advantages over the prior art.

THE INVENTION

[009] In accordance with a first aspect of the invention, a drive arrangement is provided for a pump, a compressor or the like, adapted to provide alternating pressure in a chamber, such as

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3/27 as a pump chamber or a compressor, as a result of alternating movement of a rod element. The stem element is connected to a movable face of the pressure chamber, such as a piston or a membrane, and the stem element is supported in a housing in an alternating manner. The drive arrangement additionally comprises an electric motor which is adapted to provide reciprocating movement of the rod element. The drive arrangement is characterized by the fact that the rod element travels through the rotor of the electric motor.

[0010] The pressure chamber face can be one of a plurality of types. In general, it is a face, the movement of which results in a change in volume in the pressure chamber to which it faces. It can, for example, be a piston that can be mounted on the rod element. It can also be a membrane in a membrane pump that is mechanically connected to the rod element. In addition, it can be a moving part of a pump pressure chamber. The rod element can be connected to the pressure chamber mechanically or via a fluid connection. In this way, the rod element can be a piston, for example, from which the movement energy is hydraulically transferred to a pump or a compressor.

[0011] The rod element is a part that runs through the rotor of the electric motor. The rotor can be a rotating part of a rotating electric motor, or a non-rotating part of a linear electric motor. The rod element is thus a piece that connects the motor's movement energy to the pressure chamber face. This can happen directly or indirectly.

[0012] The rotor of the electric motor can be arranged in a fluid chamber that is confined at least by said housing and by at least one movable face of the pressure chamber. The housing of the

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4/27 drive arrangement displays a wall that helps to confine the fluid chamber.

[0013] The number of movable pressure chamber faces that contribute to confining the fluid chamber can advantageously be two. These two pressure chamber faces are preferably connected to a rod element on each respective side of the electric rotor, so that a balance of force is provided between the two pressure chambers, when they detect the supply pressure in said chamber.

[0014] The fluid chamber is preferably filled with liquid.

This results in a plurality of advantages that will be described in more detail below. However, it can also be filled with gas.

[0015] The movable faces of the pressure chamber can be pistons, whose mutual distance is kept substantially constant by the rod element to which they are connected. In this way, the volume in the fluid chamber is also kept constant. This results in less floating pressure in the fluid chamber during the movement of the pistons. Furthermore, it should be noted that there is no advantage of any compression work performed on the fluid in the fluid chamber.

[0016] The drive arrangement can be connected to pumps or compressors, with which said two movable pressure faces co-operate. Advantageously, a pressure face works with one of the two pumps or compressors. The two pumps or compressors can be connected to the same source for the media to be pumped or compressed. This advantageously results in the pressure in said means on the inlet side of the respective pump or compressor being substantially the same.

[0017] The electric motor can preferably be a rotary motor and the drive arrangement can comprise an assembly of

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5/27 ball screws for converting the rotational movement of the electric motor into a linear movement of the rod element. The ball screw assembly is considered to comprise all types of arrangements suitable for converting the rotational movement of the rotational motor into a linear movement of the rod element. In addition to converting the movement from rotational to linear, a force transmission can also advantageously take place. The drive arrangement can also comprise a plurality of ball screw assemblies. The position of the rod element is preferably determined by the number of revolutions performed on the rotor of the electric motor. The axial position of the stem element can thus be advantageously monitored by reading the number of revolutions.

[0018] The drive arrangement can be adapted to generate electrical energy using the electric motor as a generator, when the speed of its movement decreases. In this way, an energy efficient drive arrangement is obtained, where parts of the structured kinetic energy can be recovered to exit the drive arrangement as electrical energy. The transfer of kinetic energy from a drive arrangement in a delay phase through the motor and the control system to one or more motors from other drive (s), which are simultaneously in the acceleration phase, allows the preservation of energy necessary for rotational and linear movement within the entire pump arrangement less losses.

[0019] In embodiments where the fluid chamber is filled with a liquid, it can advantageously be the same liquid as on the opposite sides of the pressure chamber faces. A possible leak on the pressure chamber faces will then be less important. [0020] Furthermore, when the fluid chamber is filled with a

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6/27 liquid, it can preferably be adjusted under a pressure that is greater than the pressure on the opposite sides of the pressure chamber faces. This ensures that a possible leak will happen in a direction outside the fluid chamber.

[0021] The drive arrangement can additionally comprise a lockable fluid connection between a first and a second chamber. Such connection or channel is suitable for adjusting the position of the rod element and the pressure chamber faces, as well as for regulating the amount of fluid in the chambers.

[0022] According to a second aspect of the invention, a pump assembly is provided which comprises two drive arrangements and pumps or compressors connectable thereto. The drive arrangements are adapted to provide alternating pressure in the chambers of said pumps or compressors as a result of an alternating movement of a rod element, where the rod element is supported in a housing in an alternating manner, and where each drive arrangement additionally it comprises an electric motor which is adapted to provide the changing movement of the rod element. The pump assembly is characterized by the fact that the rod element travels through the rotor of the electric motor, being connected on each side of the electric motor to a movable face of the pressure chamber, such as a piston or a membrane, whose movement results in pressure change in said chambers where the pressure change results in a pumping or compression function.

[0023] The drive arrangements in such a pump assembly, according to a second aspect of the present invention, can be operated with a mutual phase difference. This will allow for a uniform pump flow if the pump assembly is connected to the same source to which it will be pumped. An advantageous result

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Corresponding 7/27 can be achieved with respect to charging a power supply.

[0024] The possibility of a precise position control allows travel curves for the drive arrangement, which can be freely chosen within the drives that work in the envelope, based on torque, inertia, speed, travel distance, current and voltage available. The pump will continue to deliver a constant flow, as long as the different travel curves for the speed of all rod assemblies are kept at a constant sum at all times. This requires that the combined speed change satisfies dv / dt = 0. The result of a constant combined instantaneous speed with a fixed active piston area is a constant flow of pumped medium. This also means that the time period in which one of the drives is accelerated must correspond to the time period that another drive arrangement uses for delay. This will keep the sum of the acceleration and power constant over time. Acceleration and delay can also be zero, this also results in a constant combined speed.

[0025] According to a preferred embodiment, the drive arrangements in an assembly of two or more drive arrangements comprise an electric motor controller that is adapted to control the electric motor according to the behavior of another drive arrangement in the assembly . Advantageously, the travel curve of a first electric motor, or drive arrangement, will thus be adapted to the travel curve of a second electric motor or drive arrangement. This allows a pump flow to be adapted based on the inherent consistency of the pumped media. The consistency of the pumped media can, for example, be affected by the existence of impurities, such as particles,

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8/27 stones, bubbles, larger amounts of gas. Malfunction (s) can also be compensated (s) within the permitted operating envelope of the drives.

[0026] A drive arrangement and a pump assembly, according to the first or second, respectively, aspects of the invention, will advantageously confer a compact construction, low complexity, low weight, few parts, ease of use of a high torque motor, as well as a different propeller positioning.

[0027] Additional advantageous features are described in the claims.

Example

[0028] In order to provide a better appreciation of the various technical characteristics and functions of the present invention, an exemplary description of an embodiment will be provided below. The description is provided with reference to the drawings, in which:

[0029] figure 1 shows a known displacement pump with crankshaft and crosshead;

[0030] figure 2 shows a schematic main drawing of an advantageous embodiment of an aspect of the present invention;

[0031] figure 3 shows schematic main sketches of a membrane pump and a hose membrane pump;

[0032] figure 4 shows an alternative embodiment of the drive unit in figure 2;

[0033] figure 5 shows a cross-sectional view of a more realistic implementation of the drive unit in figure 2;

[0034] figure 6 shows a perspective view of a ball screw for converting rotational movement into linear movement;

[0035] figure 7 shows a cross-sectional view of the screw

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9/27 of spheres in figure 6;

[0036] figure 8 shows a perspective view of a pump assembly according to the second aspect of the present invention;

[0037] figure 9 shows a cross-sectional view of the pump assembly in figure 8;

[0038] figure 10 shows graphs for electrical energy, pump power and rotor speed for a drive arrangement according to the invention.

[0039] figure 11 shows advantageous alternatives to the curves in figure 10;

[0040] figure 12 shows a protective arrangement to protect the drive arrangement from damage due to excessive forces;

[0041] figures 13 to 19 show several curves that describe the alternating movements performed by the drive arrangements in a pump assembly;

[0042] figure 20 shows an advantageous embodiment, with respect to motor control;

[0043] figure 21 shows another embodiment of the drive arrangement according to the first aspect of the invention; and

[0044] figure 22 shows a detailed cross-sectional view, illustrating a preferred embodiment of the drive arrangement.

[0045] In figure 1, a known displacement pump with crankshaft and crosshead is shown. As can be seen from the figure, relatively large space and heavy elements are required for the crankshaft and crosshead, despite the fact that the engine is not included. In the following example of embodiment, a drive unit is described that replaces that which is within the dotted line of figure 1, and which additionally comprises the

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10/27 drive motor.

[0046] In figure 2, a schematic principle outline of a drive arrangement 11 for a first and second diaphragm pumps 13a, 13b is shown. Diaphragm pumps 13a, 13b each have their inlet valve 15a, 15b and their outlet valve 17a, 17b, respectively.

[0047] The inlet and outlet valves open and close depending on the pressure difference over them. The valves could also be controlled in another way, for example, electrically or hydraulically. The incorporated arrows show the flow directions for the diaphragm pumps 13a, 13b.

[0048] The invention, however, is not limited to membrane pumps or the pump like these. The drive arrangement according to the invention can thus be used, for example, to operate a compressor or other device. In figure 3, schematic main sketches are shown for a diaphragm pump 13a, such as those shown in figure 2, as well as for a hose diaphragm pump 13c. It is assumed that pumps and compressors are known to the person skilled in the art and therefore will not be further described here. Alternatively, the drive arrangement 11 for such arrangements will be described in more detail.

[0049] Again, reference is made to figure 2. The drive arrangement 11 comprises a cylindrical housing 19. In the housing 19, a first and second pistons 21a, 21b are arranged which are connected together with a piston rod 23. The pistons are supported against the inner wall face of housing 19 with seals 25a, 25b, such that they form a barrier against each side of the respective piston 21a, 21b. The pistons could also be arranged in an additional cylinder or sleeve on the inside

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11/27 of the housing 19. On the left side of the first piston 21a, a first functional chamber 27a is thus provided between the first piston 21a and the membrane 29a of the first membrane pump 13a. Correspondingly, a second functional chamber 27b is provided between the second piston 21b and the membrane 29b of the second membrane pump 13b.

[0050] In the central part of the housing 19, an electric motor 31 is arranged. The electric motor 31 is arranged in a fluid chamber 41 between the first and second pistons 21a, 21b. The motor stator 31a is connected to the inner wall of the housing 19. The motor rotor 31b is arranged radially within the stator 31a. The power supply of the electric motor 31 is not shown. The piston rod 23 is arranged radially within the rotor 31b, such that the rotor 31b can rotate freely with respect to it. The electric motor 31 can preferably be a permanent magnet motor.

[0051] A nut 33a is connected to the rotor 31 b, in such a way that the nut 33a rotates with the motor 31b. The nut 33a is a part of a ball screw assembly 33 and is engaged with the slots in the piston rod 23, such that the rotation of the nut 33a results in the axial movement of the piston rod 23. The slots in the piston rod 23 piston 23, which are engaged with nut 33a, are not shown. The first and second pistons 21a, 21b can thus be moved axially by rotating the electric motor 31. Furthermore, the axial direction can be determined by the direction of rotation of the rotor 31b.

[0052] It will be noted that the invention is not limited to the type of arrangement that is used to convert the rotational movement of the electric motor 31 into axial movement of the piston rod 23. One skilled in the art may thus be able to choose the transmission arrangement most appropriate energy source, for example, with respect to forces, speeds, weight, volume, loss of energy,

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12/27 maintenance, reliability and price.

[0053] Depending on the area of use for the drive unit, a gear ratio between the electric motor 31 and the nut 33a can be used, such as with a planetary gear.

[0054] Now reference will be made to figure 5, which represents a cross section of a more realistic example of the drive arrangement shown in figure 2. The fluid chamber 41 between the first and second pistons 21a, 21b can be advantageously filled with a liquid. The liquid can be of a plurality of types, depending on the area of use for the drive arrangement. For many applications, however, oil will be advantageous. The moving parts, such as the electric motor 31 and the ball screw 33 (nut 33a), will then be well lubricated. At the same time, the liquid will contribute to the cooling of the electric motor 31.

[0055] A specific advantage with the use of liquid in the housing 19 is that the actuation arrangement will then be particularly well suited for use at high pressures, for example, at great depths of the sea. Additionally, if the diaphragm pumps 13a, 13b (figure 2) are connected to the same source, the pressure in this source will act on both sides of the drive arrangement, which is on the left and right side, respectively, of the first and second pistons 21a, 21b. In this way, the electric motor does not have to work against constant back pressure, as it would have to do, if it operated only one piston. Yet another advantage is that the pressure drop on the pistons 21a, 21b becomes less, thereby reducing the appearance of leakage on the seals 25a, 25b. This arrangement will be particularly advantageous if the actuating means in the first and the second functional chamber 27a, 27b are the same liquid as in the fluid chamber 41 between the first and the second pistons 21a, 21b. A leak over the seals 25a, 25b

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13/27 will then have an insignificant role. In addition, the liquid in the fluid chamber 41 may advantageously be adjusted under pressure, so that the liquid has a higher pressure than the liquid outside the pistons 21a, 21b. A possible leak will then occur in the direction outside this fluid chamber 41, so that the liquid here is not contaminated. This will result in a long service life and reliability of the layout. A liquid in the fluid chamber 41 will advantageously both cool and lubricate the electric motor 31 and other mechanical moving parts, such as the ball screw arrangement 33.

[0056] Once the fluid chamber 41 between the first and other pistons 21a, 21b is filled with a fluid, either a liquid or a gas, the fluid will have to flow beyond the electric motor 31 and the ball screw 33 ( nut 33a), when the pistons move axially. A cut 37 is therefore suitably arranged between the piston rod 23 and the rotor 31b. The fluid may also flow through a cut between stator 31a and rotor 31b.

[0057] Instead of liquid, in some cases, it may be advantageous to use gas in the fluid chamber 41. Less fluid friction will then arise as a result of the flows than with a liquid. This can be particularly advantageous with light equipment that will move quickly.

[0058] In a suitable embodiment, a lockable fluid connection (not shown) is arranged between the first and second functional chambers 27a, 27b. Pistons 21a, 21b can be moved without pumping. In this way, the pistons 21a, 21b can be adjusted or corrected in a correct or desired position, or adjust the amount of fluid in the functional chambers 27a, 27b. Such a fluid connection can also be used to heat the internal media and in a starting sequence. In addition, it is advantageous to have one or

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14/27 plus valves to access the fluid chamber 41. In this way, the liquid can be circulated in this chamber in a circulation outside the housing 19. This allows the liquid to be heated or cooled, as well as to be cleaned and / or replaced of the liquid without having to dismantle the drive arrangement.

[0059] With the provision of a temperature meter (not shown) in connection with the liquid in the fluid chamber 41, a motor control can be advantageously arranged, which regulates the motor's performance in relation to the measured temperature. In this way, a guarantee against too much heat can be provided, as well as ensuring a sufficiently high temperature in the liquid, when applying speeds that require a certain minimum temperature in the liquid.

[0060] To prevent the piston rod from turning with the nut 33a, an anti-rotation arrangement in the form of a crossbar is provided

35. The crossbar 35 is attached to the piston rod 23 and extends in the transverse direction with respect to it. At its two ends, the crossbar 35 is engaged with guide slits that extend axially longitudinally along the inner wall of the housing 19. In this way, the crossbar 35 prevents the piston rod 23 (or the pistons) from rotating in in relation to housing 19. Other ways of preventing this rotation can also be devised. For example, the pistons and the housing may have a non-concentric cross section.

[0061] At each end of housing 19 in figure 5, flanges 39a, 39b are provided for connection to a pump or compressor (not shown).

[0062] Instead of using a liquid as the driving means, for transferring forces from the pistons 21a, 21b to the membranes 29a, 29b, as in the example referring to figure 2, the driving arrangement can also drive pumps or compressors by

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15/27 mechanical transmission of forces. Instead of one (or two) piston (s), the drive arrangement can therefore be connected directly, for example, to the diaphragm in a diaphragm pump. The arrangement shown in figure 2 can also be used without the membranes 29a, 29b. The pistons 21a, 21b will then be in direct contact with the media that are pumped.

[0063] A specific advantage with a drive arrangement, as shown with reference to figure 2 or figure 5, is that the entire drive arrangement can be hermetically sealed. Therefore, there is no need for dynamic seals. Studying the arrangement shown in figure 2, it can thus be noted that the two membranes 29a, 29b and the housing 19 form an enclosed space. However, a valve (not shown) can be advantageously arranged in the housing 19 for a possible pressure test or fluid refill in the housing 19.

[0064] Figure 4 shows an alternative embodiment of the assembly shown in figure 2. The assembly in figure 4 is only connected to a pump. On the right side of the assembly, piston 21b is maintained, but the chamber corresponding to the second functional chamber 27b in the figure is ventilated, for example, in the direction of atmospheric pressure or can be filled with gas. With the second piston 21b, it is possible to obtain the possibility of pressurizing the fluid chamber 41, and therefore obtaining the advantages mentioned above, despite the fact that the actuation arrangement is only operating a pump.

[0065] Figure 6 shows a perspective view of a ball screw assembly 33 'that can be used in a drive arrangement, as described with reference to the figure

2. The ball screw assembly 33 'has a nut 33a' on a piston rod 23 '. The piston rod 23 'has helical grooves with which the nut 33a' is engaged. One rotation of the nut

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16/27

33a 'then results in a movement of the nut along the length of the piston rod 23'. The piston rod 23 in the actuation arrangement in figure 2 naturally only needs to display such grooves in the length of the desired stroke area. Figure 7 shows the same ball screw assembly 33 'as in Figure 6 in cross section (grooves are not shown). As mentioned above, the drive arrangement according to the invention is not limited to the arrangements shown for converting rotational motion to linear motion.

[0066] In figures 8 and 9, a specific example of embodiment is shown for the application of a drive arrangement, such as that described above according to the first aspect of the invention. The figures show a pump assembly 101 comprising two drive arrangements 103 of the type shown in figure 2, as well as four hose diaphragm pumps 105. The inlets of the four hose diaphragm pumps 105 are advantageously connected to the same source and the their outputs are also combined, so that the pump assembly 101 functions as a logic pump unit. As in the drive unit described with reference to figure 2, the inlets of the hose diaphragm pumps 105 are in their respective inlet valves 15 'and their outlets are in their respective outlet valves 17'.

[0067] As indicated, the drive arrangements 103 can preferably be of the type described above in this description.

[0068] For each drive arrangement, an electrical power supply socket 107 is provided for the operation of the respective electric motor 31.

[0069] In order to connect the functional chambers 27 'of the drive arrangements 103 to the hose diaphragm pumps 105,

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17/27 fluid channels in the form of connecting tubes 109 between the functional chambers 27 'and the hose diaphragm pumps 105. The connecting tubes 109 form a part of a common chamber, comprising the functional chambers 27' in the arrangements actuators 103 and chambers 27 (figure 9) on the outside of membranes 111 of pumps 105.

[0070] In figure 9, the hose diaphragm pumps are shown in greater detail. The membranes are hose-shaped and extend between the inlet valve 15 'and the outlet valve 17'. Valves 156 ', 17' are check valves.

[0071] The other components of the pump assembly 101 shown in figures 8 and 9 are described above with reference to figures 2 and 5.

[0072] With the use of two electric motors 31, that is, one motor in each drive arrangement 103, they can be advantageously driven in such a way that they rotate in opposite directions. In this way, the torsional moment of the entire pump assembly 101 can be neutralized.

[0073] Two hose diaphragm pumps 105 that are connected to the same drive arrangement 103 will, with this configuration, be driven in the opposite phase. This means that when one pump 105 receives greater pressure from the drive arrangement 103, the other pump 105 will receive a lower pressure. In addition, with the pump assembly 101 shown in figures 8 and 9, the two drive arrangements 13 can be driven in such a way that one runs a quarter of a cycle or 90 ° behind the other.

[0074] It is also possible to design more than two drive arrangements 103 in a pump assembly. For example, three or more drive arrangements can be arranged which are connected, for example, to six or more pumps. Thus,

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18/27 a somewhat constant pumping of the means to be pumped can be provided, something that will reduce the wear of the mechanical parts. In a six-pump arrangement, for example, pumping can be performed with each pump at 60 degrees of a 360 degree cycle. Or the pumps can be arranged so that they overlap, for example, such that each pump is adapted to pump for 70 degrees of a 360 degree cycle. The first five and the last five degrees in the functional length of each pump can then be common with the previous pump and the next pump, respectively, in the cycle.

[0075] A specific advantage with the use of the electric motor in the drive arrangement is the possibility of measuring the piston rod travel. Figure 10 represents an example of pumping at full stroke length (stroke direction), where all the rotational energy from the motor (and the nut and a possible gear device) is transferred to the pump media (the liquid between the pistons 21a, 21b and membranes 29a, 29b in figure 2). As can be seen from the rotor speed graph for the electric motor rotor, the process can, in general, be divided into an acceleration phase where the rotor speed increases, a constant phase where the rotor speed is relatively uniform, and a final lag phase where the rotor speed decreases to zero rotation. In addition, it will be typical that the closer to the end of the cycle, the more electrical energy will be used to propel the pistons to the final position.

[0076] Figure 11 shows an example of pumping at full stroke length, where a portion of the rotational energy is transferred to the pump means, where the remaining rotational energy is taken back using the motor to decelerate the rotation. The electric motor works just like a generator in the last part of the

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19/27 stroke length. The generated electrical energy can, for example, be temporarily stored in a capacitor battery or transferred directly to another electric motor, for example, in another drive arrangement.

[0077] An electrical control of the electric motor therefore advantageously gives many possibilities for an advantageous control of the motor. The motor speed can be adjusted, its acceleration and torque, based on parameters such as, for example, which media should be pumped and their condition (temperature, viscosity, specific gravity, etc.) and the condition of the drive arrangement (temperature , type of fluid in the fluid chamber, age, etc.). Additionally, auto frequency can be advantageously taken into account when determining the desired speed.

[0078] With the arrangement according to the invention, an electric rotating permanent magnet motor can be advantageously used. In addition, the electric motor can be an asynchronous motor or a synchronous motor. Electric motors of types that exhibit high power efficiency and high torque will be advantageous. Additionally, both DC and AC motors can be used.

[0079] Instead of changing the direction of rotation of the electric motor to an opposite direction of travel following, a ball screw arrangement or corresponding device for converting rotational motion to linear motion can also be designed, which is adapted in such a way that the direction of travel changes automatically with the direction of rotation of the electric motor unchanged.

[0080] In an alternative embodiment, the electric motor stator can be disposed outside housing 19. The stator will then be replaced or removable for maintenance without having to open the fluid-filled chamber in the drive arrangement. The stator could also be integrated into housing 19.

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20/27

[0081] Figure 12 represents an advantageous embodiment in which the drive arrangement is provided with a clutch 145a, 145b or release mechanism. For the sake of simplicity, figure 12 shows only a few basic parts of the drive arrangement according to the invention. Corresponding to the drive arrangement described above, piston rod 123 is provided with a nut 133a for transforming the rotational movement of the electric motor into linear motion of piston rod 123. Pistons 121a, 121b are arranged at each end of piston rod 123 . In order to prevent piston rod 123 from turning with nut 133a, a linear guide 135 is engaged with piston rod 123. The linear guide can, for example, be one of the following types: splined shaft, key, polygonal shaft or similar. The linear guide 135 allows the piston rod 123 to move linearly, while maintaining it in a constant rotational position. Thus, during normal operation, there is a rotational force between the linear guide 135 and the piston rod 123.

[0082] In the event of an unforeseen or excessive load on piston rod 123, it is desirable to let piston rod 123 rotate with nut 133a in order to stop its linear movement and relieve it from excessive torques. For this to be possible, a clutch arrangement comprising an internal clutch part 145a and an external clutch part 145b is provided. The external clutch part 145 is rotatably attached to the housing (not shown). When an excessive torque force is exerted on the internal clutch part 145a and the linear guide 135 of the piston rod 123, the rotational connection between the internal and external clutch parts 145a, 145b will begin to slip. As this happens, piston rod 123 will start to turn with nut 133a, and its linear motion will be stopped.

[0083] The clutch arrangement 145a, 145 can be of a

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21/27 variety of types. Functional characteristics can, for example, be based on magnets, spring forces, rolling resistance, or friction. A shear pin solution can also be devised, but this would require more work after activating the clutch or release function.

[0084] Advantageously, the torque limit of the clutch arrangement can be adjusted, for example, by adjusting a force that presses the inner and lower clutch parts 145a, 145b against each other. With such a characteristic, a mechanical safety mechanism is provided that prevents excessive forces from the pistons 121a, 121b in the fluid in which they operate.

[0085] An advantage of the clutch arrangement is that it does not impose any damage to the drive arrangement, when engaged. In addition, the drive arrangement will be ready for use immediately after activation.

[0086] An additional advantageous feature will be to adapt the drive arrangement with feedback on the electric motor in order to monitor the location where the motor, or the piston rod, respectively, is positioned at any given time. This can, for example, be done with the use of a rotational position solver that follows the motor or a linear positioning device after the linear rod movement or with the measurement of the motor impedance detected by the motor controller, and possibly used with end position sensors.

[0087] In an alternative drive arrangement, as described here, the replacement of the electric motor with a hydraulic motor can be idealized.

[0088] Figure 13 represents speed curves of two drive arrangements in a pump assembly. It can preferably be a pump assembly like the

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22/27 pump (101) described with reference to figures 8 and 9. The two driving arrangements can be the driving arrangements 103 according to the description above.

[0089] The curves in figure 13 illustrate the absolute speed of four pistons, A, B, C and D, where a first drive arrangement 103 comprises two pistons A and B, and a second drive arrangement 103 comprises two pistons C and D. With respect to the left side of figure 13, it is seen that piston A is accelerated from zero speed to a normalized speed of 1, with constant acceleration. At the end of a stroke of piston rod 23, the speed is zero. In a central position, between the two end positions of the alternating travel path, the speed is at its maximum. A cycle of a drive arrangement 103 will be executed when, according to the curves in figure 14, both pistons A and B have performed a pumping action on the connected pump 105 (see figures 8 and 9).

[0090] The curve of pistons C and D of the second drive arrangement 103 is delayed by 90 ° or a quarter of a cycle after the curve of the first drive arrangement 103. As shown in figure 13, the sum of the two curves, the first and second drive arrangements 103 are constant. That is, its added absolute speed is always 1 (normalized). This characteristic results in a pumping speed of the assembly 101, without ripples.

[0091] The relationship between the position, speed and acceleration of the piston rod 23, together with its connected pistons 21a, 21b (or A, B, C and D), is represented in figures 14, 15 and 16.

[0092] From figure 16, which illustrates the acceleration of the pistons or piston rod, it can be seen that the acceleration is alternated between a positive constant value and the negative constant value

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Corresponding 23/27. That is, from the middle position, in the middle between the two end positions of the piston rod alternating stroke path, it begins to be decelerated. This deceleration results in zero speed in the final position. The relative deceleration continues, however, but since it continues from zero speed, it is, in fact, an absolute acceleration. Therefore, from the final position, the speed increases until the piston rod reaches an intermediate position. At this point, the acceleration changes signal, and the piston rod is decelerated again until it reaches the other end position. The final position could differ from the current total stroke end position.

[0093] Figure 15 represents the resulting speeds for the two piston rods of the first and second drive arrangements 103 of the pump assembly 101 (see figures 8 and 9). As is evident from figure 15, the resulting speed curves are hat-shaped functions or triangular functions. Such functions result from the integration of the acceleration curves in figure 16.

[0094] The integration of the speed curves in figure 15 results in the second degree or quadratic curves in figure 14. The upper and lower peak points of these curves represent the end positions of the two piston rods of the two actuation arrangements.

[0095] Advantageously, according to this embodiment, there will be no sudden movement of the piston rods 23. However, the movement of the pistons can, in fact, be as irregular as necessary, within the operational envelope, to ensure the constant combined flow the pump arrangement. An additional advantage of this feature is the reduced wear on connected equipment, such as tubes and valves.

[0096] Figure 17 shows the torques on the two respective piston rods 23 of each drive arrangement 103 of the assembly of

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24/27 pump 101. The detected induced acceleration of the respective electric motors 31 of the two drive arrangements 103 is like the torque curves with a periodic time equal to half of the other curves. The force acting on the piston rod from the engine, through the assembly of ball screw 33, will be constant between two intersections from an intermediate position. However, since the direction of the electric motor changes in the final position, the torque curves are part-time in relation to the other curves shown. This means that the power delivered to the pump assembly 101 with the two drive arrangements 103 will be kept constant, as seen from the power grid. Figure 18 shows the same curves as in Figure 17; however, with some indications referring to the acceleration and delay of the two drives, indicated as drive I and drive II.

[0097] Figure 19 represents how the piston rod speed curves change with respect to the pump speed. In order to maintain a constant sum of the two speeds of the first and the second drive arrangement 103, when a first drive reduces its speed, the second drive arrangement will have to reduce its speed accordingly, so that its cycles are the same length. In figure 19, this is shown with two different speeds VA and VB. As shown in the figure, the cycle of the first drive arrangement, here indicated with the two different cycle lengths t1A and t2A, must correspond to the cycle lengths of the second drive arrangement, that is, t1B and t2p. This will also be valid when fulfilled over partial periods.

[0098] Other curved shapes can also be designed that will keep the summarized speed constant. Such forms can be calculated by performing a mathematical approximation for the

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25/27 motor control, based on the solution of resulting differential equations. This can be performed in a real-time situation by an approximate solution based on the Galerkin method.

[0099] In addition, the use of more than two drive arrangements 103 in a pump assembly, for example, three, four or even more, can be envisaged, as long as the sums of instantaneous speeds are kept constant in time. This also does not include any combination of speed curves. [00100] A drive arrangement with a combination of ball screw arrangement and a permanent magnet motor allows very precise control of the torque and speed of piston rod 23 and connected pistons 21a, 21b. With the described embodiment, it is possible to transfer energy from a drive arrangement in a delayed state to a drive arrangement which is in an accelerated state.

[00101] In addition, in an advantageous embodiment of the pump assembly, according to the second aspect of the invention, the drive arrangements 103 are adapted to be controlled based on the behavior of another drive element 103. This is illustrated in figure 20 , showing the speed curves of two drive arrangements 103 in a pump assembly 101 (see figures 8 and 9). Each drive arrangement 103 is connected to two pumps 105 or pump heads. Sensing means and / or the motor controller (not shown) for electric motors 31 can provide input regarding the behavior of drive arrangements 103. In the situation shown in this figure, a first drive arrangement A (continuous line) changes its acceleration within a course at time t1. The reason for such a change may be a change in the pumped medium or other external or internal reasons. The second provision

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26/27 of drive B (dashed line) is adapted to this change in order to maintain a constant summary speed (fluid chamber. The continuous horizontal curve). In this way, it changes its delay at time t1, according to the reduced acceleration for the first drive arrangement A.

[00102] It will be noted that the curves can be more or less arbitrary within the operating envelope of the drive arrangements, while still maintaining the constant sum of their speeds.

[00103] It will be noted from figure 20 that the curve for the first drive arrangement A does not reach its intended upper point in 1/4 of a cycle. However, it is adapted in such a way that, however, it reaches the planned lower point in 1/2 cycle. Similar observations can be made regarding the curve of the second drive arrangement B.

[00104] After the point in time, in 1/2 cycle, the acceleration of the second drive arrangement B decreases, and the first drive arrangement A decreases its acceleration correspondingly. Its summarized speed is, however, the same as before. It should be noted that the area under the speed curve within a single directional stroke represents the stroke length for that stroke.

[00105] The limiting factors are the acceleration / delay, represented here by the rate of increase or decrease of the curved lines.

[00106] Figure 21 represents a further embodiment of the drive arrangement 11 according to the first aspect of the present invention. Here, the clutch arrangement 145 and the linear guide 125 can be seen as described in detail with reference to figure 12. In addition, a spring means 204 is arranged in order to cushion any uncontrolled excessive linear movements of the piston rod 23. 22, the function of the spring means 204 is

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27/27 described in greater detail. The spring means 204 is arranged in such a way that it can slide with respect to a first sleeve 203. In addition, a second sleeve 202 can slide with respect to the housing 219. If piston rod 223 moves all the way in the direction on the right in figure 22, a ring 201 will be forced against the first sleeve

203, which guides the force through the second sleeve 202 over the spring means

204.

[00107] If piston rod 223 moves all the way to the left in figure 22, an edge 8 on piston rod 223 will be forced against the edge of sleeve 209 of the first sleeve 203, causing the first sleeve 203 guide the pulling force that compresses the spring means 204 from the right side. The spring means 204 is pressed against the housing 219. Advantageously, the characteristics of the spring means 204 can be adapted to the desired braking stroke.

[00108] Using a spring means 204 in order to cushion an uncontrolled or excessive movement of the piston rod 23 in both directions, a compact design is obtained. The spring means 204 can be of a plurality of types, for example, Belleville springs.

[00109] The drive arrangement according to the first aspect of the present invention, or the drive arrangements used in the pump assembly according to the second aspect of the present invention can advantageously produce a pressure rise of up to 9 MPa (90 bar ) at a capacity of 3000 l / min. More preferably, they can even produce a pressure rise of up to 12MPa (120 bar) in a capacity of 4000 l / min.

[00110] It is noted that additional embodiments are possible. The scope of the invention is limited by the claims, and one skilled in the art will be able to carry out a plurality of changes to the above mentioned examples that leave the scope of the invention.

Claims (15)

1. Drive arrangement (11) for a pump, compressor or similar, which provides alternating pressure in at least two chambers (27a, 27b, 27 ', 27) of the pump, compressor or similar, as a result of an alternating movement of a bar element (23), the bar element at its respective ends is connected to a movable face of the pressure chamber, the movable face of the pressure chamber is a piston (21a, 21b) or piston, the bar element (23) is alternately supported in a housing (19), and in which the drive arrangement still comprises an electric motor (31) that provides the alternating movement of the bar element (23), characterized by the fact that the electric motor is a permanent magnetic electric rotary motor (31); the bar element extends through the rotor (31b) of the electric motor (31), and a rotational to linear transformation means (33) is functionally connected between the bar element and the motor rotor, in such a way that the rotation the rotor results in linear movement of the bar element; a linear guide (35, 135) is functionally connected between the bar element (23) and the housing (19), in order to prevent rotation of the bar element in relation to the housing; wherein the drive arrangement (11) further comprises a release mechanism (145, 145a, 145b) having a first clutch part (145a) connected to the linear guide (35, 135) and a second clutch part (145b) connected housing (19); and in which, by means of excessive rotational force between the first and second clutch parts, the rotational connection between the first and second clutch parts will slide, in order to let the bar element rotate along with the motor rotor and Petition 870190114964, of 11/08/2019, p. 34/43 2/6 interrupt your linear movement. 2. Drive arrangement according to claim 1, characterized by the fact that the drive arrangement can be ready for use immediately after the release mechanism has acted. 3. Drive arrangement according to claim 1, characterized by the fact that the functional characteristics of the release mechanism are based on magnetism or friction. 4. Drive arrangement according to claim 1, characterized by the fact that the drive device comprises a spring means (204) that dampens excessive longitudinal movements of the bar element. 5. Drive arrangement according to claim 4, characterized by the fact that the spring means (204) is arranged on an axial side of the electric motor and dampens excessive longitudinal movements of the bar element as the spring means it is compressed in a first direction by a first glove in excessive movement of the bar element in a first direction, and in a second direction by a second glove in excessive movement of the bar element in a second direction. 6. Pump assembly (101) comprising: two drive arrangements (103), where each drive arrangement is connected separately to two pumps (105) or compressors; wherein the two drive arrangements (103) are controlled on the basis of a current behavior of another drive arrangement to maintain a constant sum of the respective instantaneous speeds of the two drive arrangements; Petition 870190114964, of 11/08/2019, p. 35/43 3/6 wherein each of the two drive arrangements (103) provides alternating pressure in the chambers (27) of said pumps (105) or compressors separately as a result of reciprocating movement of a respective bar element (23) in each arrangement drive; wherein the bar element (23) is alternately supported in a housing (19) of the two drive arrangements, and where each drive arrangement (103) still comprises an electric motor (31) which provides for the reciprocating movement of the drive element bar (23), characterized by the fact that: the electric motor is a permanent magnetic electric rotary motor; the bar elements extend through the rotor (31b) of the respective electric motor (31) and a rotational to linear transformation means (33) is functionally connected between the bar element and the motor rotor, in such a way that the rotation the rotor results in linear movement of the bar element; the bar elements are each connected to a pair of pistons or pistons, the pistons or pistons of which provide said alternating pressure; and the two pumps or compressors are of a type adapted to pump or compress a fluid when activated by said alternating pressure. 7. Pump assembly according to claim 6, characterized by the fact that the bar elements of the two actuating arrangements are executed with a 90 degree phase difference in a constant reciprocating movement. 8. Pump assembly, according to claim 7, characterized by the fact that the acceleration of the bar elements and the electric motor, respectively, when moving between two Petition 870190114964, of 11/08/2019, p. 36/43 4/6 end points of an alternating movement path of the respective bar elements, always have an absolute value greater than zero. 9. Pump assembly according to claim 8, characterized by the fact that the acceleration of the bar element and the electric motor, when moving between the two end points of the reciprocating movement path of the respective bar elements, exhibits a constant absolute acceleration value. 10. Drive arrangement (11) for a pump, compressor or similar, which provides alternating pressure in at least two chambers (27a, 27b, 27 ', 27), such as pump or compressor chambers, as a result of movement alternating of a bar element (23), where the bar element at its respective ends is connected to a movable pressure chamber face being formed as a piston (21a, 21b), in which the bar element (23) it is alternately supported in a housing (19), and in which the drive arrangement still comprises an electric motor (31) that provides the alternating movement of the bar element (23), characterized by the fact that the electric motor is a rotary motor electric; the bar element extends through the rotor (31b) of the electric motor (31), and a rotational to linear transformation means (33) is functionally connected between the bar element and the motor rotor, in such a way that the rotation the rotor results in linear movement of the bar element; and the rotor (31b) of the electric motor (31) and the rotational to linear transformation means (33) are arranged in a fluid chamber (41) which is confined by at least said housing (19) and said pistons ( 21a, 21b), and the fluid chamber is filled with a liquid; and Petition 870190114964, of 11/08/2019, p. 37/43 5/6 where the liquid flows beyond the motor rotor when the bar element alternates. A drive arrangement according to claim 10, characterized in that the fluid chamber (41) is pressurized at a higher pressure than a pressure on the opposite sides of the pistons (21a, 21b). 12. Pump assembly (101) comprising: two drive arrangements (103), where each drive arrangement is separately connected to two pumps (105) or compressors; wherein each of the two drive arrangements (103) provides alternating pressure in the chambers (27) of said pumps (105) or compressors separately as a result of an alternating movement of a respective bar element (23) in each drive arrangement; wherein the bar elements (23) are alternately supported in a housing (19) of the two drive arrangements, and where each drive arrangement (103) still comprises an electric motor (31) that provides for the reciprocating movement of the drive element bar (23), and where the bar elements of the two actuating arrangements are executed with a 90 degree phase difference in a constant alternating movement, characterized by the fact that: the electric motor is a permanent magnetic electric rotary motor; the two drive arrangements generate electric energy through the use of their electric motors, by delaying a movement of the electric rotary motor, the generated energy is transferred to the electric motor of the other drive arrangement in the pump assembly during an acceleration phase of another drive arrangement, Petition 870190114964, of 11/08/2019, p. 38/43 6/6 or powered back to a power source; the bar elements extend through the rotor (31b) of the respective electric motor (31) and a rotational to linear transformation means (33) is functionally connected between the bar element and the motor rotor, in such a way that the rotation the rotor results in linear movement of the bar element; the bar elements are each connected to a pair of pistons or pistons, the pistons or pistons of which provide said alternating pressure; and the two pumps or compressors are of a type adapted to pump or compress a fluid when activated by alternating pressure. 13. Pump assembly, according to claim 12, characterized by the fact that the acceleration of the bar elements and the electric motor, respectively, when moving between two end points of an alternating movement path of the respective bar elements, always has an absolute value greater than zero. 14. Pump assembly, according to claim 13, characterized by the fact that the acceleration of the bar elements and the electric motor, when moving between the two end points of the reciprocating movement path of the respective bar elements, exhibits a constant absolute acceleration value. 15. Pump assembly according to claim 12, characterized by the fact that the two drive arrangements (103) are controlled on the basis of a current behavior of another of the drive arrangements to maintain a constant sum of the respective instantaneous speeds of the two drive arrangements.